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[R] Citrus spp. (Rutaceae).
Fr: Agrumes; Ge: Zitrone; Sp: Narango; It: Agrumi; Pt: Citrinos.
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- Thorny fruit trees, of short height (4 to 9 m), round in appearance, with evergreen leaves (*) , including different species cultivated for their fruits (citrus fruits): lemon, orange, grapefruit, mandarin-orange, clementine-orange, etc.
- The fruits of different sizes and weights, are oblong or round. The skin is yellow, orange or green, and contains oil glands. The endocarp is divided into sections (9 to 16), each composed of small juicy segments. The fruit ripens from November to June.
- Propagation is from seeds, cuttings or suckers. They are grafted around May on 2-year-old rootstock, obtained from seeds, and are planted in the following year. Harvest dates vary with the crop; lemons are harvested throughout the year, the rest of the varieties of citrus fruit being harvested during winter.
- In Europe, citrus trees are cultivated in Mediterranean countries, Spain being the primary producer.
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- Diseases: two are particularly serious: the tristeza virus, which has already destroyed millions of trees, and is transmitted by an aphid. The only defence is the use of resistant or tolerant varieties and compatible graft-rootstock combinations; greening, caused by a bacterium, is transmitted by psyllids.
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- Principal European pests: those causing the most damage are scale insects: the California red scale (Aonidiella aurantii), the (Mytilicoccus beckii), the fluted scale (Icerya purchasi), the citrus mealybug, Pseudococcus citri (Risso) (Hom., Pseudococcidae).
Various mites puncture the leaves and fruits, including the citrus rust mite, Phyllocoptruta oleivora (Ashmead) (Ac., Eriophyidae).
Also causing damage is the citrus sucker, Diaphorina citri Kuwayama (Psyllidae). The black citrus aphid (Toxoptera aurantii) and the (Aphis spiraecola) attack flowers and new growth. Also encountered are the citrus root nematode (Tylenchulus semipenetrans) and the leopard moth (Zeuzera pyrina).

[R] Images

* Lemon-tree bough and section of a fruit (Minost C.)
1: lemon-tree bough.
a: stem; b: leaf simple; c: flowers solitary or in small groups, white and very perfumed; d: lemon;.
2: transversal section of a fruit.
a;b;c: fleshy hairs; d: pip.

To read this page in French

HYPPZ on line: Species (scientific names), Pests (common names), Glossary, Crops.

HYP3 : HYPP Phytopathology.

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